A Framework for Studying Hydrology-Driven Landslide Hazards in Northwestern US Using Satellite InSAR, Precipitation and Soil Moisture Observations: Early Results and Future Directions

Zhong Lu,Jinwoo Kim

doi:10.3390/geohazards2020002

Abstract

The mountainous Pacific Northwest is prone to heavy winter rainfall, resulting in hundreds of landslides per year, human casualties, and billions of dollars of property damage. Precipitation is a major hydrologic trigger for landslides in the northwestern US and around the world. This paper reviews existing literature to outline a framework to study the linkage between precipitation and landslide hazards over the northwestern US using satellite remote sensing techniques including interferometric synthetic aperture radar (InSAR) methods, Tropical Rainfall Measuring Mission (TRMM) satellite precipitation products, and Soil Moisture Active Passive (SMAP) satellite soil moisture data, along with correlation analysis and numerical modeling. InSAR time-series displacements provide an indication of landslide occurrence and extent, and help characterize the basal slip surface and slide-body volume based on the law of mass conservation. Precipitation and soil moisture sensed from the space and ground contribute to creating hydrogeological models associated with water infiltration. These crucial parameters are tracked through correlation and slope stability analysis to understand landslide dynamics. We highlight the results on mapping landslides over the state of Washington and analyses at a few select sites over southern Washington and southwestern Oregon. We conclude that satellite observations of landslide motions and the attributing hydrological variables from both radar and optical images improve our understanding of the inter-relationships between the hydrologic processes along with topographic and geologic settings, and the landslide kinematics and mechanisms inferred from time-series measurements and landslide modeling on a regional scale.

Highlights

Landsliding is the downhill movement of soil and/or rock under the force of gravity [1]
Recurring remote sensing datasets are still facing challenges in identifying and characterizing rapidly-developing shallow landslides and avalanches because the temporal resolution of the data is not frequent enough to capture the dynamic motions of catastrophic landslides which often can exceed the ability of satellite-based remote sensing techniques
Because of the steep terrain and high precipitation in winter, landslides are common in the western Pacific

Summary

Introduction

Landsliding is the downhill movement of soil and/or rock under the force of gravity [1]. This important geomorphic process sculpts the landscapes by transporting large volumes of sediment through the fluvial system [2,3]. The other landslide category exhibits relatively slow motions along a large hillslope, following visco-elastic or visco-plastic behaviors over a long period of time [14,15,16] or coastal marine erosion on the landslide toe [17]. Landslide debris can bulk or add volume and density to otherwise normal stream flow, or cause channel blockages and diversions creating localized erosions or catastrophic flooding. Remote sensing data are better fit to monitoring slowly moving, deep-seated landslides

Methods

Results

Discussion

Conclusion